Housings normally have a very weak spring inside to return buttons like Zoom to their original positions. When the salts start to calcify around the external shaft, it leads to a bit of resistance which overpowers this weak spring.
If that seems to be the case, you can do some fairly simple DIY with a set of small gauge tools (same sizes to fix glasses) and a weak acid solution (White vinegar and water ratio 1:4) to clean the shaft of salt. Re-lube the small O-rings on the shaft with camera lube and take a test dive with the empty housing.
Helps to take photos of the disassembly process so you don't get muddled up and forget what goes where, and in which order.
If that seems to be the case, you can do some fairly simple DIY with a set of small gauge tools (same sizes to fix glasses) and a weak acid solution (White vinegar and water ratio 1:4) to clean the shaft of salt. Re-lube the small O-rings on the shaft with camera lube and take a test dive with the empty housing.
Helps to take photos of the disassembly process so you don't get muddled up and forget what goes where, and in which order.
